For problems 12 to 14, do the following: (a) Make a scatter diagram of the
scores; (b) describe in words the general pattern of correlation, if any; (c) figure
the correlation coefficient; (d) figure whether the correlation is statistically significant
(use the .05 significance level, two-tailed); (e) explain the logic of what
you have done, writing as if you are speaking to someone who has never heard
of correlation (but who does understand the mean, deviation scores, and hypothesis
testing); and (f) give three logically possible directions of causality, indicating
for each direction whether it is a reasonable explanation for the correlation
in light of the variables involved (and why).
12. Four research participants take a test of manual dexterity (high scores mean better dexterity)
and an anxiety test (high scores mean more anxiety). The scores are as follows.
(c)
(e)
(d)
(f)
Person Dexterity Anxiety
1 1 10
2 1 8
3 2 4
4 4 -2
13. Four